1. Field of the Invention
The present invention relates to an apparatus for conveying a sheet-like recording material, which includes a recording material feeding device for feeding the sheet-like recording material to a drum from a feeding guide disposed along a direction tangential to the drum, and a recording material ejecting device for sending the recording material, which has been fed from the recording material feeding device, from the drum to an ejecting guide disposed along the direction tangential to the drum.
2. Description of the Related Art
Technology has been developed in which, using a sheet-like recording material, and particularly a printing plate precursor including a photosensitive layer formed on a substrate, an image is recorded directly with a laser beam or the like on the photosensitive layer (an emulsion surface) of the printing plate precursor (printing plate exposure apparatuses). With such technology, images can be rapidly recorded on printing plate precursors.
In an automatic printing plate exposure apparatus using such technology for recording an image onto a printing plate precursor, the printing plate precursor is fed from a plate-like feeding guide to a drum in an exposure section, and the printing plate precursor is received by the exposure section, and is registered at a predetermined position and is exposed.
When the exposure is completed, the printing plate precursor is sent from the drum to the plate-like ejecting guide, and is then conveyed for further processing to, for example, a developing apparatus.
For this type of printing plate exposure apparatus, various attempts have been made to improve work efficiency in feeding and ejecting the printing plate precursor to and from the exposure section.
In a first prior art, the feeding guide and the ejecting guide are disposed near to each other in their thickness direction. When feeding a printing plate precursor, the printing plate precursor is fed from the feeding guide to a drum with a leading edge chuck detachably attached on the drum, being positioned on an extension line from the feeding guide. Then, a leading edge of the printing plate precursor is held by the leading edge chuck with a squeeze roller closely contacting the printing plate precursor to the drum. After the printing plate precursor is wound around the drum, trailing edge of the printing plate precursor is held by a trailing edge chuck. At the time of ejecting the printing plate precursor, the trailing edge of the printing plate precursor is released from the trailing edge chuck and the drum is rotated in a reverse direction. When the leading edge chuck reaches a position on an extension line of the ejecting guide, the leading edge of the printing plate precursor is released from the leading edge chuck.
In the first prior art, the position at which the leading edge chuck holds the leading edge and the position at which the leading edge chuck releases the leading edge are different. Therefore, after the previous printing plate precursor has been ejected, the drum must be moved and be registered to a printing plate precursor feeding position to receive and hold the next printing plate precursor.
In a second prior art, a feeding device for feeding a printing plate precursor and an ejecting device for ejecting a printing plate precursor are provided at completely different positions on a drum (for example, at positions 180xc2x0 apart from each other).
The second prior art includes many components, and the structure is complicated.
In a third prior art, one guide is used for feeding and ejecting a printing plate precursor. Therefore, a position at which the printing plate precursor is held by a leading edge chuck and a trailing edge chuck and a position at which the printing plate precursor is released from the leading edge chuck and the trailing edge chuck are the same.
However, in the third prior art, since the path to feed and eject the printing plate precursor is the same, it is unable to make the next printing plate precursor to stand by at a position near the drum. Therefore, work efficiency is significantly lowered.
In view of the aforementioned, an object of the present invention is to improve work efficiency by providing an apparatus for conveying a sheet-like recording material which restricts the number of components and reduces the complexity of the apparatus structure, and also by shortening the time required to start feeding the next recording material after finishing ejecting the previous recording material.
A first aspect of the invention is an apparatus for conveying a sheet-like recording material, comprising: a feeding device for feeding the sheet-like recording material to a rotating drum from a feeding guide disposed in a direction tangential to the drum; and an ejecting device for ejecting the recording material fed by the feeding device from the drum to an ejecting guide disposed in a direction tangential to the drum, wherein the feeding guide and the ejecting guide are disposed near each other in a thickness direction thereof, and the drum is in the same rotational position when feeding of the recording material to the drum is started and when ejection of the recording material from the drum is completed.
Since the feeding guide and the ejecting guide are disposed near to each other in the thickness direction thereof, the rotational position of the drum when the recording material is completely ejected from the drum can be the same as the rotational position where the next recording material begins to be fed to the drum. Therefore, the drum need not be further rotated when replacing the recording materials, thereby improving work efficiency.
A second aspect of the invention is an apparatus for conveying a sheet-like recording material, comprising: leading edge chucks, fixed at an area on a circumferential surface of a drum, for nipping and holding a leading edge of the recording material against the circumferential surface of the drum; a winding device for winding the recording material around the circumferential surface of the drum by rotating the drum in a state in which the leading edge of the recording material conveyed along a flat plate-like feeding guide is held by the leading edge chucks; an unwinding device for unwinding the recording material from the circumferential surface of the drum by rotating the drum in a direction opposite to a direction in which the drum is rotated by the recording material winding device, causing the leading edge chucks to release the leading edge of the recording material, and sending the recording material to a flat plate-like ejecting guide; and a stop control device for stopping the drum so that the leading edge chucks are located in the same position when the recording material is wound around the circumferential surface of the drum by the recording material winding device and when the recording material is unwound from the circumferential surface of the drum by the recording material unwinding device.
By making the rotational position of the drum when the recording material is completely ejected from the drum the same as the rotational position where the next recording material begins to be fed to the drum, the drum need not be further rotated when replacing the recording materials, thereby improving work efficiency.
Further, the leading edge chucks can be fixed at a predetermined position of the drum.
A third aspect of the invention is an apparatus for conveying a sheet-like recording material, comprising: leading edge chucks, fixed at an area on a circumferential surface of a drum, for nipping and holding a leading edge of the recording material against the circumferential surface of the drum; trailing edge chucks, detachably disposed with respect to another area of the circumferential surface of the drum, for nipping and holding a trailing edge of the recording material against the circumferential surface of the drum; a winding device for winding the recording material around the circumferential surface of the drum by rotating the drum in a state in which the leading edge of the recording material conveyed along a flat plate-like feeding guide is held by the leading edge chucks, and, when the recording material has been wound around the circumferential surface of the drum, holding the trailing edge of the recording material with the trailing edge chucks; an unwinding device for unwinding the recording material from the circumferential surface of the drum by rotating the drum in a direction opposite to a direction in which the drum is rotated by the recording material winding device in a state in which the trailing edge of the recording material is released from the trailing edge chucks, causing the leading edge chucks to release the leading edge of the recording material, and sending the recording material to a flat plate-like ejecting guide; and a stop control device for stopping the drum so that the leading edge chucks are located in the same position when the recording material is wound around the circumferential surface of the drum by the recording material winding device and when the recording material is unwound from the circumferential surface of the drum by the recording material unwinding device.
By making the rotational position of the drum when the recording material is completely ejected from the drum the same as the rotational position where the next recording material begins to be fed to the drum, the drum need not be further rotated when replacing the recording materials, thereby improving work efficiency.
Further, the leading edge chucks can be fixed at a predetermined position of the drum, and trailing edge chucks can also be attached and detached at the same position of the drum for holding and releasing the recording material.
In the third aspect, the feeding guide may be disposed nearer to the drum than the ejecting guide is.
When the feeding guide is disposed nearer to the drum than the ejecting guide, the recording material can be fed securely to the drum from the feeding guide and ejected from the drum to the ejecting guide by effectively utilizing the rigidity of the recording material.
Further, in the third aspect, the apparatus may further comprise a squeeze roller disposed in the vicinity of the drum and downstream, in a recording material winding direction, from a position at which the leading edge chucks are located when rotation of the drum is stopped, with the squeeze roller being movable in a radial direction of the drum.
By disposing the squeeze roller movable in the radial direction of the drum, the recording material can be securely wound around the circumferential surface of the drum. Particularly, the leading and trailing edges of the recording material can be guided to appropriate positions when the recording material is wound around the circumferential surface of the drum.
Also, in the third aspect, the drum may be stopped at the same rotational position when winding of the recording material on the drum is started and when unwinding of the recording material from the drum is completed, the leading edge chucks may be positioned on a line extending along a conveyance line from the feeding guide when the drum is stopped, and the squeeze roller may be positioned on a line extending along a conveyance line from a tip of the ejecting guide to the circumferential surface of the drum when the recording material is unwound from the drum.
Since the path in which the recording material is fed to the drum and the path in which the recording material is ejected from the drum are substantially the same, and the drum is stopped at the same rotational position for receiving and for ejecting the recording material, the time required for ejecting and receiving the recording material can be minimized.